A survey of patients with traumatic brain injuries found those who had used marijuana were more likely to survive than those who had not used the illicit substance. The findings suggest THC, or tetrahydrocannabinol, may help protect the brain in cases of traumatic brain injury, the researchers said.

The findings, published in the October edition of The American Surgeon, suggest THC, or tetrahydrocannabinol, may help protect the brain in cases of traumatic brain injury, the researchers said. The study included 446 patients who suffered traumatic brain injuries and underwent a urine test for the presence of THC in their system. The researchers found 82 of the patients had THC in their system. Of those, only 2.4% died. Of the remaining patients who didn't have THC in their system, 11.5% died.

"Previous studies conducted by other researchers had found certain compounds in marijuana helped protect the brain in animals after a trauma," said David Plurad, MD, an LA BioMed researcher and the study's lead author. "This study was one of the first in a clinical setting to specifically associate THC use as an independent predictor of survival after traumatic brain injury."

The researchers noted that the timing of their study was "pertinent" because of current efforts to decriminalize marijuana and other research that has shown THC can increase appetite, reduce ocular pressure, decrease muscle spasms, relieve pain and alleviate symptoms associated with irritable bowel disease. But they noted that their study has some significant limitations.

"While most -- but not all -- the deaths in the study can be attributed to the traumatic brain injury itself, it appears that both groups were similarly injured," Dr. Plurad said. "The similarities in the injuries between the two groups led to the conclusion that testing positive for THC in the system is associated with a decreased mortality in adult patients who have sustained traumatic brain injuries."